Was killing Osama bin Laden legal?

Although Osama bin Laden’s killing has received general public approval from the American public, its legality has been questioned. A fundamental challenge is identifying the set of legal rules that applies. Was this an effort to capture the FBI’s most-wanted terrorist, to be judged by the standards of international human rights law? Or was it a strike against an opponent in an armed conflict, judged according to the law of war?

Most critical accounts assume that the operation should be evaluated under human rights law, and the killing was clearly problematic from this perspective. International law prohibits law enforcement in foreign territory without that nation’s consent. Moreover, lethal force is only permitted as a last resort; law enforcement personnel must try to capture criminals and bring them before the courts where justice is done. Killing all the men in a home when the only armed resistance came from a detached guesthouse would likely constitute murder had it occurred in a police raid.

But there is other law that must be considered.

International recognition of 9/11 as an armed attack, coupled with the subsequent congressional authorization for the use of military force, places U.S. counter-terrorism on a unique footing. Although the “war on terror” sounds as metaphorical as “wars” on crime and drugs, the United States has actual legal authority to wage armed conflict against al Qaeda. Bin Laden’s killing must therefore be evaluated under law of war rules, which permit enemy fighters and commanders to be killed on sight unless actually incapacitated or proactively offering surrender. Lawful wartime killing is not limited to “battlefields” (which is a descriptive rather than a legal term) nor must the opponent be resisting when struck. If a killing advances the achievement of conflict aims, is directed at a lawful object of attack without disproportionate civilian harm, and no specific law of war prohibitions are violated, then it is lawful. Available information suggests bin Laden’s killing complied with these rules.

It would have been a war crime, however, if the SEALs had been ordered not to take prisoners.

Some observers have suggested bin Laden was an assassination victim. The term generally describes politically motivated killings of public officials while the law of war limits targeting to those with military roles, even if they are civilians. As commander in chief, the president is thus subject to attack. In directing al Qaeda’s operations, so was bin Laden. Law of war rules bar “assassination” but relate to the means — employing treachery — not the object. A military helicopter assault thus poses no legal issue here.

It should be clear that facile conclusions about the killing’s legality — in either direction — are generally based on simplistic assumptions; either treating the killing as one to be judged by ordinary human rights law on the one hand and condemning it, or assuming that the law of war grants carte blanche to any killing of an enemy on the other. The reality is more complex.

David Glazier is a professor at Loyola Law School, Los Angeles, where he teaches law of war and international law. He is a former Navy surface warfare officer.